/*
 * Copyright (C) 2015-2019 Alibaba Group Holding Limited
 */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

#define PRODUCTKEY_MAXLEN           (20)
#define DEVICENAME_MAXLEN           (32)
#define DEVICESECRET_MAXLEN         (64)

#define SIGN_SOURCE_MAXLEN          (200)
#define CLIENTID_MAXLEN             (150)
#define USERNAME_MAXLEN             (64)
#define PASSWORD_MAXLEN             (65)

#define TIMESTAMP_VALUE             "2524608000000"
#define MQTT_CLINETID_KV            "|timestamp=2524608000000,_v=paho-c-1.0.0,securemode=3,signmethod=hmacsha256,lan=C|"

static void utils_hmac_sha256(const unsigned char *msg, unsigned long int msg_len, const unsigned char *key, unsigned long int key_len, unsigned char output[32]);

static void _hex2str(unsigned char *input, unsigned int input_len, char *output)
{
    char *zEncode = "0123456789ABCDEF";
    int i = 0, j = 0;

    for (i = 0; i < input_len; i++) {
        output[j++] = zEncode[(input[i] >> 4) & 0xf];
        output[j++] = zEncode[(input[i]) & 0xf];
    }
}

int aiotMqttSign(const char *productKey, const char *deviceName, const char *deviceSecret,
                     char clientId[150], char username[64], char password[65])
{
    char deviceId[PRODUCTKEY_MAXLEN + DEVICENAME_MAXLEN + 2] = {0};
    char macSrc[SIGN_SOURCE_MAXLEN] = {0};
    unsigned char macRes[32] = {0};
    int res;

    /* check parameters */
    if (productKey == NULL || deviceName == NULL || deviceSecret == NULL ||
        clientId == NULL || username == NULL || password == NULL) {
        return -1;
    }
    if ((strlen(productKey) > PRODUCTKEY_MAXLEN) || (strlen(deviceName) > DEVICENAME_MAXLEN) ||
        (strlen(deviceSecret) > DEVICESECRET_MAXLEN)) {
        return -1;
    }

    /* setup deviceId */
    memcpy(deviceId, deviceName, strlen(deviceName));
    memcpy(deviceId + strlen(deviceId), "&", strlen("&"));
    memcpy(deviceId + strlen(deviceId), productKey, strlen(productKey));

    /* setup clientid */
    memcpy(clientId, deviceId, strlen(deviceId));
    memcpy(clientId + strlen(deviceId), MQTT_CLINETID_KV, strlen(MQTT_CLINETID_KV));
    memset(clientId + strlen(deviceId) + strlen(MQTT_CLINETID_KV), 0, 1);

    /* setup username */
    memcpy(username, deviceId, strlen(deviceId));
    memset(username + strlen(deviceId), 0, 1);

    /* setup password */
    memcpy(macSrc, "clientId", strlen("clientId"));
    memcpy(macSrc + strlen(macSrc), deviceId, strlen(deviceId));
    memcpy(macSrc + strlen(macSrc), "deviceName", strlen("deviceName"));
    memcpy(macSrc + strlen(macSrc), deviceName, strlen(deviceName));
    memcpy(macSrc + strlen(macSrc), "productKey", strlen("productKey"));
    memcpy(macSrc + strlen(macSrc), productKey, strlen(productKey));
    memcpy(macSrc + strlen(macSrc), "timestamp", strlen("timestamp"));
    memcpy(macSrc + strlen(macSrc), TIMESTAMP_VALUE, strlen(TIMESTAMP_VALUE));

    utils_hmac_sha256((unsigned char *)macSrc, strlen(macSrc), (unsigned char *)deviceSecret,
                      strlen(deviceSecret), macRes);

    memset(password, 0, PASSWORD_MAXLEN);
    _hex2str(macRes, sizeof(macRes), password);

    return 0;
}

/******************************
 * hmac-sha256 implement below
 ******************************/
#define SHA256_KEY_IOPAD_SIZE   (64)
#define SHA256_DIGEST_SIZE      (32)

/**
 * \brief          SHA-256 context structure
 */
typedef struct {
    unsigned long int total[2];          /*!< number of bytes processed  */
    unsigned long int state[8];          /*!< intermediate digest state  */
    unsigned char buffer[64];   /*!< data block being processed */
    int is224;                  /*!< 0 => SHA-256, else SHA-224 */
} iot_sha256_context;

typedef union {
    char sptr[8];
    unsigned long long int lint;
} u_retLen;

/*
 * 32-bit integer manipulation macros (big endian)
 */
#ifndef GET_UINT32_BE
#define GET_UINT32_BE(n,b,i)                                \
    do {                                                    \
        (n) = ( (unsigned long int) (b)[(i)    ] << 24 )             \
              | ( (unsigned long int) (b)[(i) + 1] << 16 )           \
              | ( (unsigned long int) (b)[(i) + 2] <<  8 )           \
              | ( (unsigned long int) (b)[(i) + 3]       );          \
    } while( 0 )
#endif

#ifndef PUT_UINT32_BE
#define PUT_UINT32_BE(n,b,i)                                \
    do {                                                    \
        (b)[(i)    ] = (unsigned char) ( (n) >> 24 );       \
        (b)[(i) + 1] = (unsigned char) ( (n) >> 16 );       \
        (b)[(i) + 2] = (unsigned char) ( (n) >>  8 );       \
        (b)[(i) + 3] = (unsigned char) ( (n)       );       \
    } while( 0 )
#endif


static void utils_sha256_zeroize(void *v, unsigned long int n)
{
    volatile unsigned char *p = v;
    while (n--) {
        *p++ = 0;
    }
}

void utils_sha256_init(iot_sha256_context *ctx)
{
    memset(ctx, 0, sizeof(iot_sha256_context));
}

void utils_sha256_free(iot_sha256_context *ctx)
{
    if (NULL == ctx) {
        return;
    }

    utils_sha256_zeroize(ctx, sizeof(iot_sha256_context));
}

void utils_sha256_starts(iot_sha256_context *ctx)
{
    int is224 = 0;
    ctx->total[0] = 0;
    ctx->total[1] = 0;

    if (is224 == 0) {
        /* SHA-256 */
        ctx->state[0] = 0x6A09E667;
        ctx->state[1] = 0xBB67AE85;
        ctx->state[2] = 0x3C6EF372;
        ctx->state[3] = 0xA54FF53A;
        ctx->state[4] = 0x510E527F;
        ctx->state[5] = 0x9B05688C;
        ctx->state[6] = 0x1F83D9AB;
        ctx->state[7] = 0x5BE0CD19;
    }

    ctx->is224 = is224;
}

static const unsigned long int K[] = {
    0x428A2F98, 0x71374491, 0xB5C0FBCF, 0xE9B5DBA5,
    0x3956C25B, 0x59F111F1, 0x923F82A4, 0xAB1C5ED5,
    0xD807AA98, 0x12835B01, 0x243185BE, 0x550C7DC3,
    0x72BE5D74, 0x80DEB1FE, 0x9BDC06A7, 0xC19BF174,
    0xE49B69C1, 0xEFBE4786, 0x0FC19DC6, 0x240CA1CC,
    0x2DE92C6F, 0x4A7484AA, 0x5CB0A9DC, 0x76F988DA,
    0x983E5152, 0xA831C66D, 0xB00327C8, 0xBF597FC7,
    0xC6E00BF3, 0xD5A79147, 0x06CA6351, 0x14292967,
    0x27B70A85, 0x2E1B2138, 0x4D2C6DFC, 0x53380D13,
    0x650A7354, 0x766A0ABB, 0x81C2C92E, 0x92722C85,
    0xA2BFE8A1, 0xA81A664B, 0xC24B8B70, 0xC76C51A3,
    0xD192E819, 0xD6990624, 0xF40E3585, 0x106AA070,
    0x19A4C116, 0x1E376C08, 0x2748774C, 0x34B0BCB5,
    0x391C0CB3, 0x4ED8AA4A, 0x5B9CCA4F, 0x682E6FF3,
    0x748F82EE, 0x78A5636F, 0x84C87814, 0x8CC70208,
    0x90BEFFFA, 0xA4506CEB, 0xBEF9A3F7, 0xC67178F2,
};

#define  SHR(x,n) ((x & 0xFFFFFFFF) >> n)
#define ROTR(x,n) (SHR(x,n) | (x << (32 - n)))

#define S0(x) (ROTR(x, 7) ^ ROTR(x,18) ^  SHR(x, 3))
#define S1(x) (ROTR(x,17) ^ ROTR(x,19) ^  SHR(x,10))

#define S2(x) (ROTR(x, 2) ^ ROTR(x,13) ^ ROTR(x,22))
#define S3(x) (ROTR(x, 6) ^ ROTR(x,11) ^ ROTR(x,25))

#define F0(x,y,z) ((x & y) | (z & (x | y)))
#define F1(x,y,z) (z ^ (x & (y ^ z)))

#define R(t)                                        \
    (                                               \
            W[t] = S1(W[t -  2]) + W[t -  7] +      \
                   S0(W[t - 15]) + W[t - 16]        \
    )

#define P(a,b,c,d,e,f,g,h,x,K)                      \
    {                                               \
        temp1 = h + S3(e) + F1(e,f,g) + K + x;      \
        temp2 = S2(a) + F0(a,b,c);                  \
        d += temp1; h = temp1 + temp2;              \
    }

void utils_sha256_process(iot_sha256_context *ctx, const unsigned char data[64])
{
    unsigned long int temp1, temp2, W[64];
    unsigned long int A[8];
    unsigned int i;

    for (i = 0; i < 8; i++) {
        A[i] = ctx->state[i];
    }

    for (i = 0; i < 64; i++) {
        if (i < 16) {
            GET_UINT32_BE(W[i], data, 4 * i);
        } else {
            R(i);
        }

        P(A[0], A[1], A[2], A[3], A[4], A[5], A[6], A[7], W[i], K[i]);

        temp1 = A[7];
        A[7] = A[6];
        A[6] = A[5];
        A[5] = A[4];
        A[4] = A[3];
        A[3] = A[2];
        A[2] = A[1];
        A[1] = A[0];
        A[0] = temp1;
    }

    for (i = 0; i < 8; i++) {
        ctx->state[i] += A[i];
    }
}
void utils_sha256_update(iot_sha256_context *ctx, const unsigned char *input, unsigned long int ilen)
{
    size_t fill;
    unsigned long int left;

    if (ilen == 0) {
        return;
    }

    left = ctx->total[0] & 0x3F;
    fill = 64 - left;

    ctx->total[0] += (unsigned long int) ilen;
    ctx->total[0] &= 0xFFFFFFFF;

    if (ctx->total[0] < (unsigned long int) ilen) {
        ctx->total[1]++;
    }

    if (left && ilen >= fill) {
        memcpy((void *)(ctx->buffer + left), input, fill);
        utils_sha256_process(ctx, ctx->buffer);
        input += fill;
        ilen  -= fill;
        left = 0;
    }

    while (ilen >= 64) {
        utils_sha256_process(ctx, input);
        input += 64;
        ilen  -= 64;
    }

    if (ilen > 0) {
        memcpy((void *)(ctx->buffer + left), input, ilen);
    }
}

static const unsigned char sha256_padding[64] = {
    0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};

void utils_sha256_finish(iot_sha256_context *ctx, unsigned char output[32])
{
    unsigned long int last, padn;
    unsigned long int high, low;
    unsigned char msglen[8];

    high = (ctx->total[0] >> 29)
           | (ctx->total[1] <<  3);
    low  = (ctx->total[0] <<  3);

    PUT_UINT32_BE(high, msglen, 0);
    PUT_UINT32_BE(low,  msglen, 4);

    last = ctx->total[0] & 0x3F;
    padn = (last < 56) ? (56 - last) : (120 - last);

    utils_sha256_update(ctx, sha256_padding, padn);
    utils_sha256_update(ctx, msglen, 8);

    PUT_UINT32_BE(ctx->state[0], output,  0);
    PUT_UINT32_BE(ctx->state[1], output,  4);
    PUT_UINT32_BE(ctx->state[2], output,  8);
    PUT_UINT32_BE(ctx->state[3], output, 12);
    PUT_UINT32_BE(ctx->state[4], output, 16);
    PUT_UINT32_BE(ctx->state[5], output, 20);
    PUT_UINT32_BE(ctx->state[6], output, 24);

    if (ctx->is224 == 0) {
        PUT_UINT32_BE(ctx->state[7], output, 28);
    }
}

void utils_sha256(const unsigned char *input, unsigned long int ilen, unsigned char output[32])
{
    iot_sha256_context ctx;

    utils_sha256_init(&ctx);
    utils_sha256_starts(&ctx);
    utils_sha256_update(&ctx, input, ilen);
    utils_sha256_finish(&ctx, output);
    utils_sha256_free(&ctx);
}

static void utils_hmac_sha256(const unsigned char *msg, unsigned long int msg_len, const unsigned char *key, unsigned long int key_len, unsigned char output[32])
{
    iot_sha256_context context;
    unsigned char k_ipad[SHA256_KEY_IOPAD_SIZE];    /* inner padding - key XORd with ipad  */
    unsigned char k_opad[SHA256_KEY_IOPAD_SIZE];    /* outer padding - key XORd with opad */
    int32_t i;

    if ((NULL == msg) || (NULL == key) || (NULL == output)) {
        return;
    }

    if (key_len > SHA256_KEY_IOPAD_SIZE) {
        return;
    }

    /* start out by storing key in pads */
    memset(k_ipad, 0, sizeof(k_ipad));
    memset(k_opad, 0, sizeof(k_opad));
    memcpy(k_ipad, key, key_len);
    memcpy(k_opad, key, key_len);

    /* XOR key with ipad and opad values */
    for (i = 0; i < SHA256_KEY_IOPAD_SIZE; i++) {
        k_ipad[i] ^= 0x36;
        k_opad[i] ^= 0x5c;
    }

    /* perform inner SHA */
    utils_sha256_init(&context);                                      /* init context for 1st pass */
    utils_sha256_starts(&context);                                    /* setup context for 1st pass */
    utils_sha256_update(&context, k_ipad, SHA256_KEY_IOPAD_SIZE);     /* start with inner pad */
    utils_sha256_update(&context, msg, msg_len);                      /* then text of datagram */
    utils_sha256_finish(&context, output);                            /* finish up 1st pass */

    /* perform outer SHA */
    utils_sha256_init(&context);                              /* init context for 2nd pass */
    utils_sha256_starts(&context);                            /* setup context for 2nd pass */
    utils_sha256_update(&context, k_opad, SHA256_KEY_IOPAD_SIZE);    /* start with outer pad */
    utils_sha256_update(&context, output, SHA256_DIGEST_SIZE);     /* then results of 1st hash */
    utils_sha256_finish(&context, output);                       /* finish up 2nd pass */
}